Hydraulic jar



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July 14, T953` 2 Sheets-Sheet l Filed Aug. 6, 1951 July 14, 19:53 l w.N. s-UTLIFF 2,645,459

HYDRAULI JAR Patented .uly 1.4,

Wayne N. Sutli", Bakersfield, Calif. Application August c, 1951,seria1N0.240,4s7

This invention relates to an oil well tool and particularly to ahydraulic well jar of the typev including a hammer and anvil, in whichthe hammer is retarded when urged toward the anvil to tension the drillstring or wire supporting the well jar, and then released to cause aviolent impact between the hammer and anvil. The present application isa continuation-in-part application of my prior co-pending applicationentitled,

Hydraulic Well Jar and Method of Use, Serial No. 49,973, iiled September18, 1948, now abandoned.

As is well known to those skilled in the art, Well I jars are connectedto twistedoff strings of drill pipe and other objects that become lodgedor stuck in well bores for the purposes of jarring the lodged or stuckmembers in an effort to loosen them for removal.

Hydraulic well jars of the type described above have the advantage ofbeing simple in construction, including few parts, and wearing lessrapidly than mechanical well jars. However, these hydraulic well jarshave not been dependable in operation, in many instances functioning foronly a few jars and then ceasing to operate properly, necessitatingtheir removal and adjustment or repair. I believe that this defect inoperation is caused by the creation of voids in the hydraulic fluidchamber in the well jar.` 'I believe that .these voids Idetrimentallyaffect the operation of such a well jar by preventing the-extent ofretardation of the hammer necessary to sufliciently tension the drillstring or wire line to cause a violent impact between the hammer andanvil upon release of the hammer. These voids may be formed or createdinseveral ways. Thehydraulic fluid chamber may notbe entirely filledwhen the -well jar is prepared forA use.` The high internal hydraulicpressures created in the well jar on the high pressure side of thehammerV during operation may cause leakage past the packing'on the highpressure side, or leakage can occur past the other packing in the welljar.

It i'sa main object of the present invention to provide a hydraulic welljar having a hydraulic iluid chamber including a compensating floatingpiston. exposed on one side. to the pressure of the well iluid andon theopposite side to the low pressure side of the hammer, so that when thewell jar is lowered into a well, the pressure of the well f the volumethereof is equal to the hydraulic fluid therewithin, whereby existingvoi-ds in the hydraulic fluid chamber are eliminated and the 4 claims.(01255-27) Ii-formation of new voids ncausable by leakage of hydraulicfluid from the chamber is prevented. This floating compensating pistonstructure is disclosed in my prior co-pending application aboveidentified.

Another object of the present invention is to provide an improvedhydraulic well jarjparticularly one having an improved valvearrangement. The valve arrangement of the present application, thoughbeing broadly similar to, is specifically `different from the one shownin my prior identilied co-pending application.

Various other objects will be apparent from the following descriptiontaken in connection with f the accompanying drawings, wherein:

Fig. 1 discloses a well jar embodying the concepts of the presentinvention being shown in quarter section. Y

Fig, 2 is an enlarged sectional View, through a portion of the well jardisclosed in Fig. 1, showing the valve closed and the hammer in theprocess of being pulled upwardly toward the anvil.

Fig. 3 is a View, similar to Fig. 2, showing the hammer after havingbeen released and` in engagement with the anvil.

Fig. 4 is a view, similar to Fig. 2,showing the hammer being moveddownwardly and the valve being open.

Fig. 5 is a View showing themanner of attachment of the hydraulic welljar to a wireline.

Referring to the accompanying drawings wherein similar referencecharacters designate similar parts throughout, the hydraulic well jarhas a' hydraulic iluid chamber formed by a valve housing 9, which has alower sub `Il secured to 'the lower end thereof, and an upper sub I3secured to the upper end of valve housing 9. This hydraulic fluidchamberis lled with a suitable hydraulic fluid, such as oil, throughports I4 in valve housing 9 closed by pipe plugs Illa.

A central composite mandrel I5 extends through the hydraulic chamberand, adjacent its upper end, sealingly `engages upper packing |1,carried by upper sub I3, and, vadjacent its ,lower end, sealinglyengages lower packing I9, carried rby lower sub I I. Above lower packingI9, there is a floating compensating annular piston/2| slide ablyreceived within valve housing sand slidably receiving the lower end ofcomposite mandrel l5. The hydraulic fluid is therefore contained withintubular housing 9 and upper sub I3 and between upper packing I'l andiioating piston 2I Further reference to the floating will be madehereinafter.

Upper packing il is adapted to be held in place by arpacking nut 23threadedly received within the upper end of upper sub I3, and lowerpacking compensating piston 2|A Y the -anvil andfluid passageways formedon the outer surface of said mandrel inwardly of the valve for bypassingthe valve when the valve is unseated, said passageways extending from apoint Vbeyond the valve seat toward the hammer and beyond theV valve andbeing closed by the valve against fluid passageV past the valve seatwhen said valve is close-d, spring means urging the valve toward itsseat to seal "off the passageways, and a floating compensating annularpiston slidably received by the chamber and slidably receiving themandrel, exposed on one side to the Vpressureofthe hydraulic fluid inthe chamber and' on its opposite side to the pressure of the vwelllfluid, operable, whenthe well jar is lowered into a well andthepistonis subjected to the well valve seat formed thereon facing axially towardY fluidin the space between the hammer and anvil operable to'suddenlyreleasethe fluid to effect a sudden movement of the-hammer toward theanvil, the improvement which comprises the provision of a passagewaycommunicating'the interior of the chamber with the exteriorthereof,

andan annular floating piston surrounding the mandrel and dimensioned tosnugly fit against the `interior, walls of the. chamber and Vonzthemandrel to seal against both members,A said pis- Y ton being exposed onone side to the pressure of fluid pressure, to eliminate existing voidsin the hydraulic fluid chamber and prevent the formation of new voids,causable by leakage of hydraulic fluid from the cham-benby shiftingunder the influence of a differential pressure created by the voids orleaking fluid to reduce the volume of the hydraulic fluid chamber to anextent-where the volume of the hydraulic fluid chamber ist;

equal to the volume of thefluid therewithin.

vthe hydraulic fluid in the chamber and on its opposite side to thepressure of the well fluid and being operable when the jar is loweredinto a well and the piston is subjected to the well fluid pressure, toeliminate existing voids in the hydraulic fluid chamber and prevent theforma- 2. A hydraulic well jar, comprising a hollow fluid-tight housingadapted to'be secured to a flsh lodged in a well and providing ahydraulic .uid` chamber deflnedl in part Iby a large bore portion and aVsmall bore portion, an anvil within the large bore portion of lthehousing, a mandrel Y adapted to be reciprocated by a drill string orwire line and slidably received within the housing and carrying a hammeradapted to be brought `into violent contact with the anvil,` an annularvalve on the mandrel dimensioned to slidably fit within the small boreand over the mandrel and being operable to retard movement of the hammertoward the mandrel when the valve is disposed within the smallbore'portion of the housing to cause tensioning of the drill string orequivalent structure and to suddenly release the hammerwhen moved to aposition within the large =bore portion of the housing to allow thehammer to violently strike the anvil, said mandrel hav- Y :ing a valveseat formed thereonV facing axially toward the anvil and fluidpassageways formed on the outer surface of said mandrel inwardly of thevalve for bypassing the valve when the valve is unseated, saidpassageways extending from a point beyond the valve seat toward thehammer and beyond the Valve and being closed by the valve against fluidpassage past the valve seat when said valve is closed, and spring meansurging the valve toward its seat lto seal off the passageways, and afloating compensating annular piston slidably received within thechamber at a point to be exposed to the pressure on the side of thehammer remote from the anvil, and slidably receiving the mandrel, andexposed on its opposite side to the pressure of the well fluid,operable, when the well jar is lowered into a well and the piston issubjected to the well fluid pressure, to eliminate existing voids in thehydraulic fluid chamber and prevent the formation of new voids, causableby leakage of hydraulic fluid from the chamber, by shifting under theinfluence of a differential pressure created by the voids or leakingfluid to reduce the volume of Vthe hydraulic fluid chamber to :an extentwhere the volume of the hydraulic fluid chamber isequal to the volume ofthe fluid therewithin.

3. In a hydraulic `well jar of the type having a hydraulic fluid chamberreciprocably receivingr tion '.of new voids, causable by leakage ofhydraulic fluid from the chamber, by vshifting under the influence ofdifferential pressure created bythe existing voids or by leaking fluidto reduce the volume of thehydraulic fluid chamber to an extert wherethe volume thereof is equal to the volume of fluid therewithin.

4. In a hydraulic well jar of the type having a hydraulic fluidchamberreciprocably receiving a mandrel, and wherein a hammer isy provided Y onone of the parts in axial alignment and adapt- Y 'lol ed to be broughtinto violent engagementwith an anvil provided on the other of the partsupon relative movement between vthe -chamber and mandrel in onedirection, the improvement which comprises the provisionof a passagewaycommunicating the interior of the chamber-with the exterior thereof, anannular resilient floating piston Vsurrounding the mandrel anddimensioned to snugly llt against the interior walls of the chamber andon the mandrel to seal against both members, said piston being exposedon one side tothe pressure of the hydraulic fluid inthe chamber andonits opposite side to the pressure of the well fluid and being operablewhen the jar is lowered into a well and the piston'is subjected to thewell fluid pressure, to eliminate existing voids in the hydraulic fluidchamber and prevent the formation of new voids, causable by leakage ofhydraulic fluid from the chamber, by shifting under the influence ofdifferential pressure created by the existing voids or by leaking fluidto reduce the volume of the hydraulic fluid chamber to 'an extent wherethe volume thereof is equal to the volume'of fluid therewithin, andmeans for trapping fluid in the space between the hammer and anviloperable to suddenly release the fluid to effect a sudden movement ofthe hammer toward the anvil, said piston being located on the side ofthe hammer remote lfrom the anvil so that it is not `subjected to theextreme pressures created in the space between the hammer and the anvil.

WAYNE N. SUTLIFF.

References Cited in the file of this patent

